Opening remarks

It is a great pleasure to me on behalf of the Technical Research Centre of Finland, VTT, to welcome you to Finland and Espoo. VTT's main campus in Otaniemi is only some three kilometres from here. In Otaniemi, VTT works in close co-operation with the Helsinki University of Technology, the largest of its kind in Finland. There are also several specialised research institutes and high-technology companies located in Otaniemi area. VTT employs some 2700 people, almost 60 % having a university degree. There has never been any dedicated nuclear research centre in Finland. However, nuclear energy research is an important part of VTT's activities and is closely coupled with other applications. We operate nowadays as a concern of nine quite independent research institutes. Indeed, six out these nine institutes are now regularly involved in nuclear R&D or provide services for the nuclear industry in Finland and abroad. In several areas, nuclear applications have been the driving force when VTT has developed new capabilities, with important spin-off effects. Simulation of dynamic industrial process systems is certainly one of the best examples in this respect, Fig. 1. In early 1970's, immediately after nuclear power plants were ordered in Finland, we started to carry out accident analyses, with the first versions of the RELAP code, for example. Analogue simulators were built already in the late sixties, followed by hybrid simulators in seventies. We also had an important role in the building of the full-scope training simulator commissioned in 1980 for the Loviisa NPR. In 1980's we started to look at the simulation of combustion power plants and in recent years we have had strong interest in paper mills, both areas being very important for the Finnish industry. We who are interested in the simulation of nuclear power plants can also benefit of spinin from other areas of technology. The huge progress in the computational fluid dynamics, CFD, helps us to improve our thermal-hydraulic modelling, and latest visualisation and virtual reality techniques offer possibilities to enlarged scope of simulation in training, in maintenance for example. Also, simulators are very useful as test beds when we have to modernise the I&C systems of nuclear power plants by introducing programmable automation systems and new control room features. About ten years ago we draw the first version of a picture illustrating the different numerical simulation tools available for nuclear power plant design, safety analysis and training, Fig. 2. At that time we had quite distinct categories of sophisticated accident analysis codes, fast-running simplified models for simulators and some early attempts to combine fidelity and comprehensiveness of the simulation in engineering simulators. Today we can draw a quite different picture, Fig. 3. The boundaries have almost vanished. Current computers allow the use of highly sophisticated models even in real- time applications and CRT based control rooms are eliminating the major difference between training simulators and plant analyzers. The major difference between a training simulator and a plant analyzer can be that the models of the analyzer must be very flexible and easy to modify. However, if training does not take all the capacity of a modem simulator, it can very well serve as a plant analyzer too. We have a lot of experience in this respect: VTT's researchers have spent many nights and weekends at the Loviisa training simulator. A strong current trend is the need for more efficient use of plant analyzers: users are no more supposed to be experts in computer and simulation technology, they should be allowed to concentrate on understanding the process being studied. The first CSNI specialist meeting on simulators and analyzers in summer 1992 attracted 86 participants from 12 countries. In this second meeting, we have 92 participants from 17 countries. This certainly indicates a real need to gather around this theme. In addition to the large number of countries present, these meetings have another distinct, very valuable character: the participants come from virtually all types of organisations involved in the nuclear power business. From the NEA viewpoint, we bring together experts working in several principal working groups of the CSNI.